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Title: Flow Induced Noise Source Modeling

Authors: Edward Tejnil, Zhidong Zhang

Abstract: Findings from a flow induced noise source modeling study are presented to develop the capability and understand limitations of current computational technologies. In particular, a case of tandem cylinders is examined from the Benchmark problems for Airframe Noise Computations (BANC) workshops. The tandem cylinders in crossflow configuration models landing-gear noise and involves two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. The spanwise extent of the tandem cylinders is limited to 3 diameters in the CFD model. The computational effort used three-dimensional, unsteady, compressible Navier-Stokes flow solver ANSYS CFX, with scale adaptive simulation (SAS) and SST turbulence model. The results of the study are compared to experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center. The experiments were conducted at Reynolds number 1.66x105 (144 ft/s) based on the cylinder diameter and employed a boundary layer trip on the upstream cylinder to insure development of fully turbulent shedding process. The computed results including steady and unsteady surface pressure data, shedding frequency and radiated noise from the cylinders show good agreement between simulation and experimental data.